Pathological Tumor–Nodal Response Patterns After Neoadjuvant Treatment for Rectal Cancer: Prognostic Impact of Residual ypN-Positive Disease

Abstract

Simple Summary Neoadjuvant treatment can completely eliminate the primary rectal tumor while residual cancer remains in regional lymph nodes or tumor deposits. This study examined whether considering primary-tumor and nodal response separately improves prognostic assessment after neoadjuvant treatment. A total of 215 patients with nonmetastatic rectal cancer who underwent curative-intent surgery were retrospectively evaluated and classified into four pathological tumor–nodal response groups. Patients with complete regression of the primary tumor and no residual nodal disease had the most favorable outcomes. In contrast, patients with complete primary-tumor regression but persistent nodal disease experienced substantially higher risks of recurrence and distant metastasis. Because only 13 patients had this uncommon ypT0N+ response pattern, these findings should be interpreted cautiously and confirmed in larger studies. These findings suggest that complete regression of the primary tumor should not be interpreted as a uniformly favorable response when nodal disease remains and support separate consideration of nodal status in postoperative risk stratification.